Sources

Using auto-pickpocketing from the master camouflage outfit did yield coins on the subsequent automatic pickpocket attempts if the timer ticked over during the run.

Alternatively, Menaphite coins could be bought for RuneCoins on the Seasonal Event interface Shop tab:

Menaphite coins

RuneCoins

Menaphite coins per RuneCoin

Price in terms of bonds

500

45

11.1

4,551,410

2,500

240

10.4

24,274,185

5,000

385

13

38,939,838

When a player received Menaphite coins, they were notified with one of the following messages:

You find X Menaphite coins and place them in your inventory. (When there was space in the player's inventory and there were no Menaphite coins in the currency pouch.)

You find X Menaphite coins and place them in your bank. (When there was no space in the player's inventory and there were no Menaphite coins in the currency pouch.)

You find X Menaphite coins. They are added to your currency pouch. (When were some already in the player's currency pouch.)

Trivia

Originally only 1,000 Menaphite coins could be obtained per day without using an event extender. Several hours later the daily cap was removed. RuneCoins for bought daily limit extenders were refunded in several days.[1]